refs #6417 this should fix some tests. Start initial value by 0 so first generated id will be 1

fix omnifixture creation was broken

refs #6417 wondering if omnifixture creation worked

refs #6417 acquire a lock per archive id which should be better

refs #6417 we have to generate the SQL in the update itself otherwise the update would fail at some point in the future if the tables signature changes

refs #6417 split updates into a separate update file otherwise it would not be executed for devs using Piwik from git

refs #6417 added some documentation

refs #6417 Piwik 2.9.0-b2 was released meaning we have to move it to b3

refs #6417 Piwik 2.9.0-b3 was released meaning we have to move it to b4